title: Electrocatalytic sulfite biosensor with human sulfite oxidase co-immobilized with cytochrome c in a polyelectrolyte-containing multilayer.
abstract: An efficient electrocatalytic biosensor for sulfite detection was developed by co-immobilizing sulfite oxidase and cytochrome c with polyaniline sulfonic acid in a layer-by-layer assembly. QCM, UV-Vis spectroscopy and cyclic voltammetry revealed increasing loading of electrochemically active protein with the formation of multilayers. The sensor operates reagentless at low working potential. A catalytic oxidation current was detected in the presence of sulfite at the modified gold electrode, polarized at +0.1 V (vs. Ag/AgCl 1 M KCl). The stability of the biosensor performance was characterized and optimized. A 17-bilayer electrode has a linear range between 1 and 60 microM sulfite with a sensitivity of 2.19 mA M(-1) sulfite and a response time of 2 min. The electrode retained a stable response for 3 days with a serial reproducibility of 3.8% and lost 20% of sensitivity after 5 days of operation. It is possible to store the sensor in a dry state for more than 2 months. The multilayer electrode was used for determination of sulfite in unspiked and spiked samples of red and white wine. The recovery and the specificity of the signals were evaluated for each sample.
authors.affiliation: Institute of Biochemistry and Biology, University of Potsdam, Karl-Liebknecht Strasse 24-25, 14476, Golm, Germany.
authors.forename: Roberto
authors.initials: R
authors.lastname: Spricigo
authors.forename: Roman
authors.initials: R
authors.lastname: Dronov
authors.forename: Fred
authors.initials: F
authors.lastname: Lisdat
authors.forename: Silke
authors.initials: S
authors.lastname: Leimkühler
authors.forename: Frieder W
authors.initials: FW
authors.lastname: Scheller
authors.forename: Ulla
authors.initials: U
authors.lastname: Wollenberger
mesh_terms: D000814:Aniline Compounds / Q000378:metabolism; D000818:Animals; D015374:Biosensing Techniques; D002384:Catalysis; D045304:Cytochromes c / Q000378:metabolism*; D004563:Electrochemistry; D004566:Electrodes; D004573:Electrolytes / Q000378:metabolism*; D004800:Enzymes, Immobilized / Q000378:metabolism*; D006046:Gold / Q000737:chemistry; D006736:Horses; D006801:Humans; D009206:Myocardium / Q000201:enzymology; D010084:Oxidation-Reduction; D050876:Sulfite Oxidase / Q000378:metabolism*; D013447:Sulfites / Q000032:analysis*; D013451:Sulfonic Acids / Q000737:chemistry
chemical_list: D000814:Aniline Compounds; D004573:Electrolytes; D004800:Enzymes, Immobilized; D013447:Sulfites; D013451:Sulfonic Acids; C416807:polyaniline; D006046:Gold; D045304:Cytochromes c; D050876:Sulfite Oxidase